NG 5pc Buff Question

I've had people tell me conflicting explanations for how the NG 5pc actually works, and want to know for sure.

Some say that when you have all Buffs, your highest Element (and/or opponent's weakest resist) is the Ele elenore that is used..
Whereas others say that only the first Buff that procs [per cycle] is the elenore that is used..

Anyone know for sure? I want to know if stacking 1 Element is better than going All Ele or not.